反应详情

3-Bromo-2,2′-bithiophene (IIIa) (3.00 g, 12 mmol) in dry diethylether (100 mL) was added slowly to a solution of n-butyllithium (1.6 M in hexane, 7.50 mL, 12 mmol) in dry diethylether (100 mL) at −78° C. over 2 h under N2. The mixture was stirred for 15 minutes at the same temperature. Freshly distilled 3-pentanone (1.29 mL, 12 mmol) was added via a syringe to the mixture at −78° C., followed by stirring overnight at room temperature. The reaction was quenched with an aqueous NH4Cl-solution (2.5 M, 50 mL) and water (50 mL) at 0° C. The organic phase was separated and the aqueous phase was extracted with diethylether. The combined organic phases were washed with brine, dried over MgSO4 and evaporated under reduced pressure to give a crude oil. The oily residue was purified by column chromatography (eluent hexane/EtOAc 90:10) to afford the title compound (IIa) as a green oil (1.7 g, 56%). 1H-NMR (CDCl3): δ=7.35 (dd, J=5.2 Hz, J=1.2 Hz, 1H), 7.24 (d, J=5.4 Hz, 1H), 7.10 (dd, J=3.6 Hz, J=1.2 Hz, 1H), 7.00 (dd, J=5.2 Hz, J=3.6 Hz, 1H), 6.95 (d, J=5.4 Hz, 1H), 1.75 (q, J=7.7 Hz, 4H), 0.80 (t, J=7.4 Hz, 6H). 13C-NMR (CDCl3): δ=145.33, 136.11, 129.99, 129.76, 128.97, 127.87, 127.40, 125.54, 79.29, 35.79, 8.80.

1. stirringby stirring overnight at room temperature
2. customThe reaction was quenched with an aqueous NH4Cl-solution (2.5 M, 50 mL) and water (50 mL) at 0° C
3. customThe organic phase was separated
4. extractionthe aqueous phase was extracted with diethylether
5. washThe combined organic phases were washed with brine
6. dry with materialdried over MgSO4
7. customevaporated under reduced pressure
8. customto give a crude oil
9. customThe oily residue was purified by column chromatography (eluent hexane/EtOAc 90:10)